EP3093392B1 - Fish lift with slider - Google Patents

Description

The invention relates to a fish lift according to the preamble of claim 1.

From the DE 10 2014 001 825 A1 a fish lift is known for transporting fish between an overflow of a barrage and an underwater of the barrage, the fish lift comprising a shaft and a container, the shaft comprising an upper opening leading into the upper water with an upper gate exit closable by an upper gate, wherein the shaft comprises a lower opening leading to the underwater with a lower lock entrance, the container being movable between an upper position and a lower position and comprising at least one lateral opening and wherein the container is designed as a floating container, which its positions in the shaft in Dependency on a shaft water level existing in the shaft.

The invention has for its object to provide a fish lift, in which regardless of a differing by several meters water level of the upper water is always a near-surface entry and exit of fish from the upper water in the container and from the container in the upper water is possible.

This object is achieved on the basis of the features of the preamble of claim 1 by the characterizing features of claim 1. In the dependent claims advantageous and expedient developments are given.

The fish lift according to the invention comprises a diaphragm and movement means for moving the diaphragm, wherein the upper opening of the shaft is at least partially closed by the diaphragm, wherein the diaphragm is vertically movable by the movement means, wherein the diaphragm comprises an opening, wherein the opening on the lateral Opening of the container is adapted such that whenever the aperture and the lateral opening of the container are aligned, fish can swim through a channel formed by the aperture and the opening, wherein the upper opening of the shaft has a height such that this extends when standing in a high upper position container to below a bottom of the container, the aperture is movable depending on a water level of the upper water between a high water position and a low water position and wherein the diaphragm with a height to the upper opening of the Shaft is adapted to this that also in their high water position, in which the container is moved to its high upper position down so over the standing in its high position above the container that the upper opening of the shaft through the panel to an interior of the shaft is closed, so that the upper water is sealed off from the interior of the shaft. This makes it possible, regardless of a water level of the upper water to allow a near-surface entry and exit of fish from the upper water in the container and from the container in the upper water. Core of the invention is a relatively movable to the upper opening of the duct panel, which seals off the upper opening of the shaft to the extent required to an interior of the shaft.

It is also envisaged to arrange the panel between the container and an inner wall of the shaft. As a result, the panel for maintenance is easily accessible from the shaft.

It is also envisaged to arrange the panel on an outer wall of the shaft. This makes it easy to observe the operation of the aperture and to detect malfunctions.

It is also envisaged to arrange the panel in a wall of the shaft and lead. With such a design, a particularly compact construction of the fish lift is possible because the panel affects neither the installation space for the container nor the installation space for the upper slide.

Furthermore, it is provided to guide the panel on at least one rail. In this way, the rail can be given a precise movement, so that an undesired tilting is prevented. Furthermore, it is envisaged to guide the panel in the area in which the panel must also withstand the pressure of the upper water, in order to achieve a reliable foreclosure of the interior of the shaft against the upper water.

It is also provided to form a stop for the container through the aperture, which prevents the container from further lifting movement. This makes it possible, with simple means to determine the respective uppermost position of the container by the position of the aperture and so align the container on the panel and to ensure that di lateral opening of the container is aligned with the aperture of the aperture.

Furthermore, it is provided that the movement means comprises a controlled depending on the state of the upper water actuator, which raises the aperture with a rising level of the upper water and lowered with a falling level of the upper water. By aligning the aperture at the level of the upper water is ensured by simple means the correct position of the aperture.

Furthermore, it is provided, the actuator as electrically or form pneumatically or hydraulically driven cylinder and equip the moving means with a sensor for detecting the level of the upper water and a control device. In this way, the aperture can be controlled safely and also easy to monitor electronically.

Finally, the invention provides to form the actuator as a float, wherein the movement means also includes a connected to the panel linkage, by means of which the aperture is movable with the float. By such a mechanical coupling between the actuator and aperture high reliability of the moving means is secured. In this case, it is provided to monitor the position of the actuator and the position of the diaphragm and the water level or the level of the upper water by means of sensors.

Further details of the invention are described in the drawing with reference to schematically illustrated embodiments.

Further details of the invention will be described with reference to the schematic drawing.

Figur 1 und 2:

schematische Ansichten eines Fischlifts in zwei verschiedenen Stellungen und

Figur 3 bis 6:

schematische Ansichten eines erfindungsgemäßen Fischlifts in verschiedenen Stellungen.

Hereby show:

FIGS. 1 and 2:

schematic views of a fish lift in two different positions and

FIGS. 3 to 6:

schematic views of a fish lift according to the invention in different positions.

Based on FIGS. 1 and 2 are the components and the principle of a fish lift principle explained. The FIGS. 1 and 2 show a fish lift 1, in which an underwater 5 is at a level N5, the fish lift 1 or a barrage 4, in which the fish lift 1 is integrated, is shown in schematic, sectional side views.

The fish lift 1 is provided for transporting fish 2 between a headwater 3 of the barrage 4 and the underwater 5 of the barrage 4. The fish lift 1 comprises a shaft 6 and a container 7. In this case, the shaft 6 comprises an upper opening 8 below a level N3 of the upper water 3 with an upper lock exit 9. Furthermore, the shaft 6 comprises a lower one below the level N5 of the lower water 5 Opening 10 with a lower lock entrance 11. The container 7 is between a in the FIG. 1 shown upper position S3 and one in the FIG. 2 shown lower position S5 movable. In the shaft 6, the container 7 is guided on two opposing rails 12, 13. The container 7, which in the FIG. 1 is shown in its upper position S3, is shaped such that this surrounds the two rails 12, 13. The container 7 comprises a transport space 14. The transport space 14 forms a basin 15. The basin 15 has a basin floor 16, on which the sole substrate 17 is arranged. As a result, the basin 15 represents a largely natural environment for the fish 2 and other living beings. In its wall 18, the container 7 has a first lateral opening 19 and a second lateral opening 20 which lead into the transport space 14. Here, the opening 19 of the container 7 is aligned with the upper opening 8 of the shaft 6, when the container 7 is in its upper position S3 and in this case the opening 20 of the container 7 is aligned with the lower opening 10 of the shaft 6, when the container 7 is in its lower position S5. Like from the FIG. 2 is visible, the second lateral opening 20 is in the lower position S5 of the container 7 below the level N5 of the underwater 5 and leads to the underwater 5 and in a Einschwimmzone 21. The second lateral opening 20 of the container 7 is in its lower position the lock entrance 11 and the lower opening 10 of the shaft 6 such that at opened lock entrance 11 a relation to the container 7 surrounding the interior 22 of the shaft 6 shielded connection to the underwater 5 consists. The lock entrance 11 is formed in the second rail 13, this second rail 13 has a directed onto the opening 20 of the container 7 lower rail opening 13a. Here, the lock input 11, the opening 10, which is designed as a pipe section, a locking member 24 and an unillustrated actuating means for the locking member 24. The locking member 24 is formed as a slider 26 and the actuating means, not shown, includes actuators and a linkage. In the FIG. 2 the slider 26 is in a raised position, so that the path between the underwater 5 and the transport space 14 of the container 7 is released for the fish 2. The locking member 24 and the actuating means of the lock input 11, not shown, are arranged in a cavity of the second rail 13, not shown, and thus are protected in the shaft 6. In the transport space 14 of the container 7 and in the Einschwimmzone 21 of the underwater 5 is in in the Lower position S5 standing container 7 and open lock entrance 11 a Leitströmung L5 via a first Leitwasserversorgung 32 manufactured. The first conductive water supply 32 comprises a supply channel 33, a supply channel valve 34 and a Leitwasserdüse 35. The supply channel 33 is fed from the upper water 3, wherein the inflowing through the supply channel 33 amount of water is controlled by the supply channel valve 34. The Leitwasserdüse 35 is the first lateral opening 19 of the container 7 opposite, when this is in its lower position S5. Through the Leitwasserdüse 35 flows from the upper water 3 water as Leitströmung L5 in the transport space 14 of the container 7 and through the second opening 20 and the opened lock entrance 11 further into the underwater 5 and the Einschwimmzone 21st

The fish lift 1 further comprises a discharge device 301. This comprises a discharge lock 38, through which a drain opening 39 formed in the shaft 6 can be closed is. The discharge opening 39 is arranged below the lower opening 10 and leads into a discharge and irrigation channel 40, which leads under a bottom 41 of the Einschwimmzone 21, past the Einschwimmzone 21 in the underwater 5. As long as the container 7 is in the lower position S5, an opening of the discharge lock 38 is possibly provided when the supply channel 33 has to be flushed through. In such a case, a valve 34 'is then opened and upper water from the supply channel 33 via a bypass 35' under the container 7 passed. In this way, a flushing device 302 is formed, through which upper water can flow away under the container 7 past the Leitwasserdüse 35, without the guide flow L5 formed in the container 7 and in the Einschwimmzone 21 is thereby impaired.

The fish lift 1 further comprises a second lead water supply 49. This comprises a supply channel 50, which is fed from the upper water 3, and a supply channel valve 51. The supply channel 50 of the second lead water supply 49 flows in front of the lower lock entrance 11 in the Einschwimmzone 21 of the underwater 5. In the in the FIG. 2 shown lower position S5 of the container 7, the supply channel valve 51 is closed, so that no upper water 3 is passed through the second Leitwasserversorgung 49 into the underwater 5. The second lead water supply 49 is activated when the lock inlet 11 is closed in order to maintain the lock flow in the underwater 5. Like from the FIG. 2 further shows the lock exit 9 is closed when the container 7 is in the lower position S5 or moves to the lower position. The lock exit 9 comprises a locking member 52 and actuating means, not shown, wherein its opening 8 is formed by a pipe section, which the upper water 3 through a on the upper opening 8 of the shaft 6 and the opening 19 of the standing in the upper position S3 container. 7 aligned upper rail opening with the interior 22 of the shaft 6 connects. The locking member 52 is formed as a slider 55 and the actuating means, not shown, are formed by actuators, not shown, and a not shown linkage. Through the closed lock exit 9, the inflow of upper water 3 into the interior 22 of the shaft 6 is prevented. The container 7 is designed as a floating container 59 and includes a float 60. This gives the container 7 in the interior 22 of the shaft 6 rising water level so strong buoyancy that this floating on the rails 12, 13 from its lower position S5 and with rising water level in the shaft 6 from in the FIG. 2 shown lower position S5 in the in the FIG. 1 shown upper position S3 is moved. In this case, an increasing water level in the shaft 6 is generated by the fact that the lower lock entrance 11 is closed by the slide 26 and further supplied via the first Leitwasserversorgung 32 and / or the flushing device 302 upper water 3, wherein the discharge device 301 remains closed. An entraining flow L5 in the float zone 21 is then maintained via the second pilot water supply 49. Once the container 7 in the in the FIG. 1 shown upper position S3, there is a maintenance of the lock flow 21 in the underwater 5 additionally or alternatively via a third Leitwasserversorgung 49 ', which flows from the container 7 overflowing upper water 3 through a supply channel 50' the underwater 5 in the Einschwimmzone 21.

The upper position S3 has the container 7 - as in the FIG. 1 shown reached when the floating container 7 with its upper side 61 against a shaft 6 upwardly bound retaining means 62, which is designed as a stop 63, floats and is prevented by this at a further upward lifting movement. As soon as the container 7 rests against the stop 63, the upper lock exit 9 can be opened so that the upper water 3 flows into the transport space 14 of the container 7. A ceiling 64 of the container 7, which forms the upper side 61, has a third opening 65 on, through which the transport space 14 of the container 7 is accessible from above. Since the container 7 is held by the stop 63 with its upper side 61 below the level N3 of the upper water 3, the upper water 3, which flows through the upper lock exit 9 into the transport space 14, swells upwards out of the container 7 through the opening 65. The overflowing upper water 3 flows over an upper edge 66 of the shaft 6 and the third Leitwasserversorgung 49 'is supplied. As a result, in the transport space 14, after opening the lock exit 9, an upper guide flow 67 emanating from a discharge zone 21 'of the upper water 3, through which the fish 2 are led out of the transport space 14 into the upper water 3 or out of the upper water 3 be conducted into the transport room 14. As long as the container 7 is in its upper position S3, the lock flow L5 is maintained in the underwater 5 through the second and / or the third Leitwasserversorgung 49 and 49 '.

If necessary, it is provided to keep the supply channel valve 34 or the valve 34 'of the rinsing device 302 slightly open in order to compensate for leakage at the lower lock inlet 11 or at the discharge lock 38 and to keep the container 7 constantly against the stop 63.

At average water level N5 of the submarine 5 an attachment 201 of the fish lift 1 remains out of service. This auxiliary device 201 is designed as a pump device 202, which operates as a water drainage device and / or as a water supply device, and comprises a mechanical pump 203, a first line 204 for connecting the pump 203 to the shaft 6 and a second line 205 for connecting the pump 203 with In this case, the first line 204 opens in a bottom portion 69 'of the shaft 6 in the shaft 6 and this opens the second line 205 outside the Einschwimmzone 21 and Ausschwimmzone 21' in the environment U4 and in particular in the underwater 5 or in the upper water 3.

At average water level N5 of the underwater 5 or at a lower than the average water level N5 water level of the underwater 5, the container 7 drops when discharging contained in the interior 22 of the shaft 6 water down to lower stop means 91, so that the lateral opening 20 on the lower opening 10 of the shaft 6 is aligned.

With increased water level N5 'of the underwater, like this in the FIG. 1 is indicated, it is not possible by means of the outlet opening 39, discharge lock 38 and discharge channel 40 Ablasseinrichtung 301 to lower the container 7 in the shaft 6 to the lower stop means 91, as a shaft water level on the discharge device 301 and / or on the lower Opening 10 of the shaft 6 can only be lowered to the level N5 '. Accordingly, to lower the shaft water level then the pump 203 is activated and lowered with the help of the shaft water level W22-3 below the level N5 'so far that the container 7 assumes the position S5. Conversely, at an upper water level below the level N3 N3 '(see FIG. 2 ) Pump 203 is operated so that it promotes so much water in the shaft 6, that a shaft water level W22-1 is reached and thereby the container 7 in the in the FIG. 1 shown position S3 raised and held in this. Of course, leakages occur in this situation due to the fact that water flows out of the shaft 6 through its upper opening 8 into the upper water 3.

In the FIGS. 3 to 6 an embodiment of a fish lift 501 according to the invention in different positions at low water level N5031 an upper water 503 and at high water level N5032 of the upper water 503 is shown in schematic representations. Basically, the points in the FIGS. 3 to 6 schematically illustrated fish lift 501 also the functions and features of the in the FIGS. 1 and 2 shown fish lifts. The in the FIGS. 3 to 6 shown fish lift 501 differs from that in the FIGS. 1 and 2 In principle, the fish lift shown has a shaft 506 with an upper opening 508 which has a height H508 which is greater than a height H519 of a first lateral opening 519 of a container 507 FIGS. 3 to 6 shown fish lift 501 differs from that in the FIGS. 1 and 2 In principle, the fish lift shown further comprises an aperture 580 and a movement means 581 for vertical movement of the aperture 580. In this case, form the shutter 580 and the movement means 581 in addition to a slide 555, which can completely close and open the upper opening 508 of the shaft 506, a further closure device 582. Analogous to the illustration of FIGS. 1 and 2 is in the in the FIGS. 3 to 6 embodiment shown also an exit of fish 502 provided in an unillustrated underwater. For this purpose, the container 507 on one of the lateral opening 519 opposite, not shown opening. The height of the upper opening H508 is in an embodiment of the fish lift 501 for a reservoir or a storage lake, for example 2 to 6 meters.

In the FIG. 3 is compared with the FIGS. 1 and 2 shown about a right upper quarter of the fish lift 501. Here, the fish lift 501 is also provided for transporting fish 502 between the upper water 503 of a barrage 504 and an underwater of the barrage 504, not shown, shown in a sectional side view. From the fish lift 501, substantially the well 506 and the container 507 are visible, wherein the container 507 is in an intermediate position S535 at a central shaft water level W522-2. The shaft 506 comprises the upper opening 508 leading into the upper water 503, which forms an upper lock exit 509 which can be closed by the upper slide 555. Likewise, the shaft 506 includes a lower opening leading into the underwater with a lower lock entrance, as in the analogous FIGS. 1 and 2 is shown. The container 507 is between a high upper position S503h (see FIG. 6 ) and a low upper position S503n, in which it is aligned with its opening 519 on the upper opening 508 of the shaft 506, and a lower position, not shown, in which it is aligned with its opening 520 on a lower opening of the shaft 506 , movable. The container 507 is designed as a floating container 559, which assumes its positions S503h, S503n or S535 in the shaft 506 in response to a shaft water level W522-2 or W522-31 or W522-32 present in the shaft 506. Here is next to the in the FIGS. 3 and 5 shown middle shaft water level W522-2 in the FIG. 4 the low upper shaft water level W522-31 and in the FIG. 6 high upper shaft water level W522-32 shown. The low upper shaft water level W522-31 corresponds to the low water level N5031 of the upper water 503 and the high upper shaft water level W522-32 corresponds to the high water level N5032 of the upper water 503. The upper opening 508 of the shaft 506 is at least partially closed by the shutter 580 as the FIGS. 3 to 6 demonstrate.

In the FIGS. 3 to 6 is shown as a means of movement 581 a pneumatic cylinder 583, which is vertically displaceable by a control device, not shown, which includes a sensor, not shown, and with this the water level of the upper water 503, depending on the water level of the upper water 503. The aperture 580 in this case comprises an opening 584, which is congruent with the lateral opening 519 of the container 507. The bezel 580 also includes a stop 585 which is positioned on the bezel 580 to stop the container 507 in its upward movement when its side opening 519 is aligned with the aperture 584 of the bezel 580. This is in the FIGS. 4 and 6 low water level N5031 and high water level N5032. As an alternative to the movement means 581, a second movement means 591 is shown with dashed lines. This moving means 591 includes as an actuator a float 593, which raises and lowers the orifice 580 in response to a water level of the upper water 503 by means of a linkage 596. In the FIGS. 5 and 6 the rod 596 is cut through and only partially shown.

The FIGS. 3 and 4 show the headwater 503 at a low water level N5031. Accordingly, the aperture 580 is in a low water position NWS. By inflow of upper water 503 into an inner space 522 of the duct 506, the shaft water level rises from a central shaft water level W522-2 to a low upper shaft water level W522-31 at which the tank 507 is lifted up to the stop 585 of the shutter 580 (see FIG. 4 ). Once the container 507 has arrived in its low upper position S503n, the upper slide 555 can be opened so that - as in the FIG. 4 Fish 502 can flow from the upper water 503 into a transport space 514 of the container 507 and from the transport space 514 into the upper water 503 through the aperture 584 of the aperture 580 and through the lateral opening 519 of the container 507. Here, the lateral opening 519 and the opening 584 form a channel K502.

Analogous to the FIGS. 3 and 4 shows a consideration of FIGS. 5 and 6 how the container 507 is raised at a high water level N5032 of the flood 503 from its intermediate position S535 to the high upper position S503h. Here, the aperture 580 is at a high water level N5032 in a flood position HWS. The orifice 580 is automatically raised from its low water position NWS to its high water position HWS when the upper water 503 rises by the movement means 581 or the alternative means 591 used. The height H508 of the upper opening 508 of the duct 506 is so large that, when the tank 507 is in a high top position S503h, it extends below a bottom 507u of the tank 507. In this case, the diaphragm 580 is adjusted with a height H580 to the height H580 of the upper opening 508 of the shaft 506 such that it also in its high water position HWS (see FIG. 6 ), in which the container 507 can be moved to its high upper position S503h, projects downward over the container 507 standing in its high upper position S503h such that the upper opening 508 of the shaft 506 is closed by the diaphragm 580 to the inner space 522 of the shaft 506, such that the upper water 503 is sealed off from the interior 522 of the shaft 506 by the diaphragm 580. The shutter 580 is disposed between an inner wall 522 a of the duct 506 and the container 507. The orifice 580 is thus dimensioned such that it seals the portion of the interior 522 of the shaft 506 below the container 507 in each operating position to the upper water 503. The orifice 580 thus prevents the upper water 503 from entering through the upper opening 508 of the duct 506 directly into the part of the inner space 522 of the duct 506 located below the tank 507.

In order to keep closed the upper opening 508 of the shaft 506 even at low water N5031 of the upper water 503 to the present in the aperture 580 opening 584, it is provided according to a variant, not shown, that the aperture extends beyond its stop far away upwards in that the opening 508 is closed by the aperture 580 even in the low water position NWS of the aperture 580. This makes it possible to easily prevent, for example, waterbirds fly in low water N5031 and opened upper slide 555 in the interior 522 of the shaft 506.

According to an embodiment variant, not shown, the diaphragm is guided in a wall 518 of the shaft 506.

According to another embodiment, not shown, it is also provided to arrange the panel on an outer wall 522b of the shaft 502.

LIST OF REFERENCE NUMBERS

501

fish lift

502

fish

503

headwater

504

barrage

506

shaft

507

container

507u

Subpages of 507

508

Opening of 506

509

upper lock exit

514

Transport room of 507

518

Wall of 506

519

lateral opening of 207

522

Interior of 506

522a

Inside wall of 506

522b

Exterior wall of 506

555

upper slide

559

floating vessel

580

cover

581

means

582

Locking device from 580 and 581

583

Pneumatic cylinder as 581

584

Breakthrough of 580

585

Stop of 580

591

second means of movement

593

swimmer

596

linkage

H508

Height of 508

H519

Height of 519

H580

Height of 580

HWS

Flood position of 580

K502

channel

NWS

Low water position of 580

N5031

Low water level of 503

N5032

High water level of 503

S535

Intermediate position of 507

S503h

high top position of 507

S503n

low upper position of 507

W522-2

mean shaft water level

W522-31

low upper shaft water level

W522-32

high upper shaft water level

Claims (9)

1. Fish lift (501, 1) for transporting fish (502, 2) between an upper water (503, 3) of a barrage (504, 4) and a lower water of the barrage (504, 4), comprising

   - a hoistway (506, 6) and a container (507, 7),

   - wherein the hoistway (506, 6) comprises an upper opening (508, 8) leading into the upper water (503, 3), comprising an upper sluice outlet (509, 9) which can be closed by an upper slider (555, 55),

   - wherein the hoistway (506, 6) comprises a lower opening (10) leading into the lower water (5), which has a lower sluice inlet (11),

   - wherein the container (507, 7) can be displaced between an upper position (S503h, S503n; S3) and a lower position (S5) and comprises at least one lateral opening (519, 19), and

   - wherein the container (507, 7) is designed as a floating container (559; 59), which assumes positions (S503h, S503n, S535; S3, S5, S35) of same in the hoistway (506, 6) according to a present hoistway water level (W522-2, W522-31, W522-32; W22-1, W22-2, W22-3) in the hoistway (506, 6),

   characterised in that

   - the fish lift comprises a screen (580) and displacement means (581, 591) for displacing the screen (580),

   - wherein the upper opening (508) of the hoistway (506) can at least partially be closed by means of the screen (580),

   - wherein the screen (580) can be displaced vertically by the displacement means (581, 591),

   - wherein the screen (580) comprises a passage (584),

   - wherein the passage (584) is adapted to the lateral opening (519) of the container (507) such that whenever the passage (584) and the lateral opening (519) of the container (507) are oriented with each other, fish (502) can swim through a channel (K502) formed by the passage (584) and the opening (519),

   - wherein the upper opening (508) of the hoistway (506) has such a height (H508) that same extends to below a bottom side (507u) of the container (507) when the container (507) is in a high upper position (S503h),

   - wherein the screen (580) according to a water level (N5031; N5032) of the upper water (503) can be displaced between a high water position (HWS) and a low water position (NWS),

   - wherein the screen (580) with a height (H580) is adjusted to the upper opening (8) of the hoistway (6) such that same also in the high water position thereof (HWS), during which the container (507) can be displaced into the high upper position (S503h), protrudes downwards over the container (507) standing in the high upper position (S503h) thereof such that the upper opening (508) of the hoistway (506) is closed with respect to the inner space (522) of the hoistway (506) by the screen (580).
2. A fish lift according to claim 1, characterised in that the screen (580) is arranged between the container (507) and an inner wall (522a) of the hoistway (506).
3. A fish lift according to claim 1, characterised in that the screen (580) is arranged on an outer wall (522b) of the hoistway (506).
4. A fish lift according to claim 1, characterised in that the screen (580) is arranged and guided on a wall (518) of the hoistway (506).
5. A fish lift according to at least one of the preceding claims, characterised in that the screen (580) is guided on at least one rail.
6. A fish lift according to at least one of the preceding claims, characterised in that the screen (580) forms a stop (585) for the container (507), which prevents the container (507) from performing another lifting movement.
7. A fish lift according to at least one of the preceding claims, characterised in that the displacement means (581, 591) comprises an actuator controlled according to the level (5031; N5032) of the upper water (503), which actuator lowers the screen (580) when the upper water (503) rises and when the upper water (503) falls.
8. A fish lift according to claim 7, characterised in that the actuator is designed as an electrically or pneumatically or hydraulically driven cylinder (583) and that the displacement means (581) comprises a sensor for detecting the level of the upper water (503) and a control device.
9. A fish lift according to claim 7, characterised in that the actuator is designed as a float (593) and comprises a rod (596) connected to the screen (580), by means of which rod the screen (580) can be displaced with the float (593).

Images